1. Field of the Invention
The present invention relates to an image forming apparatus, particularly to a configuration that prevents a noise in an image forming apparatus main body from leaking to the outside.
2. Description of the Related Art
Recently, an image forming apparatus, such as a printer and a copying machine, in which a sheet is fed to an image forming portion to form an image becomes widespread. In the image forming apparatus, usually the sheet stored in a sheet cassette is automatically fed to the image forming portion. For example, a sheet feeding apparatus that feeds the sheet is provided in a lower portion of the image forming apparatus main body, and the image forming portion is provided above the sheet feeding apparatus. When an image is formed in the sheet, the sheet fed by the sheet feeding apparatus is conveyed to the image forming portion along a sheet conveying path that is vertically extended.
For an image forming apparatus of a related art, for example, in the case in which the uppermost sheet is separated using a separation pad and fed to the image forming portion, a scratch sound is generated between the separation pad and the sheet when the sheet passes through the separation pad. A scratch sound is also generated when the sheet separated by the separation pad passes through the vertically-extended sheet conveying path. The scratch sounds leak to the outside to become a noise.
In the image forming apparatus of the related art, sometimes the sheet conveying path is jammed with the conveyed sheet. In some pieces of image forming apparatus, a door that can vertically turn with a horizontally-extended turning shaft as a supporting point is provided in a side portion of the image forming apparatus main body, and the door is opened in the sheet jam, thereby opening the sheet conveying path to remove the jammed sheet. For example, Japanese Patent Laid-Open No. 02-225237 discusses the technology.
In the image forming apparatus of the related art in which the door is provided to open the sheet conveying path, it is necessary to provide a gap for the purpose of the opening and closing of the door between the door and the image forming apparatus main body such that the door does not interfere with a frame of the image forming apparatus in the neighborhood of the turning shaft in opening the door. However, when the gap is provided, the noise such as the scratch sound in the image forming apparatus main body leaks from the gap to the outside. Therefore, there is discussed an image forming apparatus in which a sound insulation member such as a sponge and an elastically-deformable thin plate is attached to the door such that the gap between the door and the image forming apparatus main body is closed to prevent the leakage of the noise. For example, Japanese Patent Laid-Open No. 2004-359364 discusses the technology.
When the sound insulation member is provided in the door, the sound insulation member collides with the image forming apparatus main body in opening and closing the door, whereby a position of the sound insulation member is shifted or the sound insulation member drops out. Additionally, the sound insulation member repeatedly collides with the image forming apparatus main body, thereby generating temporal degradation in the sound insulation member. Therefore, conventionally the sound insulation member is attached to a position that is deviated from an opening trajectory of the door between the door and the sheet conveying path.
In the image forming apparatus of the related art, recently a sheet feeding unit is optionally provided below the image forming apparatus main body in order to be able to feed sheets having various sizes and various types and a large number of sheets. Even in the option sheet feeding unit, the door is provided to remove the jammed sheet when the sheet cassette, a sheet feeding roller, a separation portion, or the sheet conveying path is jammed with the sheet.
As described above, the sound insulation member is attached to a position that is deviated from the opening trajectory of the door between the door and the sheet conveying path, for example, the position illustrated in FIG. 5. The following issue is generated in this case. That is, in the configuration in which an option sheet feeding unit 342 is attached below the image forming apparatus main body, unless an end of the sheet conveying path provided above the option sheet feeding unit 342 enters the image forming apparatus main body side, the sheet is caught by a seam of the sheet conveying path, and the sheet cannot be conveyed.
When a sound insulation member 20 is provided at the position illustrated in FIG. 5 in the configuration of the sheet conveying path, the sound insulation member 20 becomes impeditive in jam recovery when a front door 55 of the option sheet feeding unit 342 is opened. Therefore, it is necessary to detach the sound insulation member 20 when the option sheet feeding unit 342 is attached.
However, sometimes a user forgets to detach the sound insulation member. When the option sheet feeding unit is mounted while the sound insulation member is not detached, unfortunately the sound insulation member is nipped between the option sheet feeding unit and the image forming apparatus main body to break the sound insulation member.